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Homework Help: Finding freq., Wavelentgh, Phase Velocity, and attenuation constant

  1. Jan 15, 2008 #1
    1. The problem statement, all variables and given/known data



    where z is distance (m), find...

    (a) Frequency

    (b) Wavelength

    (c) Phase Velocity

    (d) At z = 2m, the amplitude is 1 [V], Find the attenuation constant ([itex]\alpha[/itex]).

    2. Relevant equations




    3. The attempt at a solution


    Using the first term ([itex]\frac{2\pi\,t}{T}[/itex]) in the argument to the cosine in the general form above...




    Using the second term ([itex]-\,\frac{2\pi\,x}{\lambda}[/itex]) in the argument to the cosine in the general form above...







    Last edited: Jan 15, 2008
  2. jcsd
  3. Jan 16, 2008 #2
    How did you eliminate 't' in part d?
  4. Jan 16, 2008 #3


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    Science Advisor

    There is no "t" in (d). The "attenuation" constant is the rate at which the magnitude of the wave degrades- and that depends entirely upon the coefficient of the cosine term, [itex]5e^{-\alpha z}[/itex]. And here, we are given that z= 2.
  5. Jan 16, 2008 #4
    What about the sin term. 1= 5xexp(-alpha x z) x sin term which contains t?
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